A TOTAL REFLECTION X-RAY-FLUORESCENCE SPECTROMETER WITH MONOCHROMATIC EXCITATION

A total reflection X-ray fluorescence spectrometer with monochromatic excitation for trace-element analysis on semiconductor wafers is presented. Using a multilayer monochromator intense monochromatic and tunable excitation is provided. The monochromatic excitation brings about a clear background reduction and produces an excitation spectrum of inherent spectral purity. Even with a low power Mo fine-focus tube, detection limits of 10(10) atoms/cm2 are attainable. The tunability of the excitation conditions allows selective excitation, which is especially advantageous for light elements. The in-line capability of the method lends itself to process control in semiconductor fabrication.